McIntosh MR73 Tuner Service Information.pdf

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1、SERVICE INFORMATION STARTING WITH SERIAL NO. 10T01 McIntosh laboratory inc. 2 chambers street binghamton, new york MR 73 MR 73 ELECTRICAL SPECIFICATIONS PM TTINER SECTION USEABLE SENSITIVITY Better than 2,5m-V (IHF useable sensitivity) SIGNAL TO NOISE RATIO Better than 70dB CAPTURE RATIO Better than

2、 1.5?dB SPURIOUS REJECTION 90dB or greater HARMONIC DISTORTION Mono, less than 0.3% Stereo, less than 0.7%. IMAGE REJECTION 75dB or greater (at 100MHz) STEREO SEPARATION FREQUENCY RESPONSE Better than 35dB at 1kHz. Flat from 20Hz to 20kHz with standard de-emphasis and 19kHz pilot filter SCA FILTER B

3、etter than 50 dB rejection from 67kHz to 74 capacitance values smaller than 1 are in microfarads (pF); capacitance values greater than 1 are in picofarads (pF); inductors are in microhenries (pH). 2. Printed circuit board components are outlined on the schematics by dotted lines. The circled numbers

4、 around the dotted lines correspond to the numbers on the PC Board layouts. 3. The heavy lines on the schematics denote the primary signal path. 4. The terminal numbering of rotary switches is for reference only. s indicated on the schematics are measured under the followi conditions Use of an 11 me

5、gohm input impedance VTVM b. All voltages _+l 0/ with respect to chassis ground or antenna terminals d. AC input at 117 volts, 50/60 Hz Front panel controls at: Tuning indicator 100MHz (no signal) AM (to measure AM section) Mode Stereo (to measure FM sect ion) Vo 1ume 6. In units with Serial Nos bel

6、ow 15T33: R434 is not used In units with Serial Nos below 15T74: R112 is 3.3k; R20 and C33 are used; R15 is connected as shown by dotted lines and center terminal of AM sensitivity switch (S2) is connected to ground as shown by dotted line. In units with Serial Nos from 24T00 to and XF-2 is McIntosh

7、 Part No. 044-045A. 3T50: C109 and C113 are not used; R106 is 680Q In units with Serial Nos below 3 3 T 5 0 : R1 0 5 is 1 0 k ; R1 0 7 S- Rl 1 3 are 100ft 10%; C4 is and L 5 Is 1 .2 pH. 10. In units with Serial Nos below 27T84: R21 is not used In units with Serial Nos below 33T50: R329 is not used;

8、R307 is 200k; there is no connection from R307 to Pin 12 of MPX PC board and Pin 14 of MPX PC board is connected to the arm of R307 only. In units with Serial Nos below 33T50, PC board 043-975 is used of Q402 and Q403 as shown by dotted 1ine. It connects the collector R409 9405 R405 C405 R407 COAX 0

9、401 R403 R4I9 C409 G405 C403 + YEL/WHT COAX R400 R408 Q4C2 RED/WHT RC04 C404 G40C R406 0404 R402 R418 R4I0 R4I2 R42? AMPLIFIER U 0) U 0; CD CC ID CC ID CC . , i- CL CL CL Qj 0) CL) cc cc CC . o o 0 1 i 1 MR 73 -p X 03 fI cd H cd rH bOrI X XI H P 03 p, P Ph fs *H Ph 0) ox 40 -P Ph 0) X x 40 p -p x X

10、cd 50 Ph H 2 O O Pi -P Pi XI Pi cd B Ph o II Ph Cd Ph 03 c 03 p -p -p X XI P m cd O Ph X H 0 bO X 3 o cd iI c. o -p p, P Pi Cd*H T3 C-P +0 rH rH 03 03 M O Cd H 03 X o cd bO cd S 3 P b0 x S B 5 Ph Eh Ph 03 X Pi rH B 03 O -P b0-H H O 03 Oh H t4 2 P -P P . rH cd Oh X Oh Pi 03 03 Ph cd O 03 03 O C3 Ph O

11、 Pi S d X P - 03 43 Cd p, 03 * cd X X Ph 03 X 40 Oh p CO O cd 03 cd Ph Pi H X 40 Ph 03 H t-P 03 03 p 03 Pi 40 0 Ph 03 03 Pi X 40 cd Oh +3 X 0 43 X Ph O X 3 W s P P 03 c BOX 40 rH 03 X3 bo Pi O O X X H *r4 H cd r! X Cd O 03 Ph H P 40 03 H *H C 0 cd cd cd O cd 43 Oh 0 X Ph 43 cd 40 p EH X X cd o X 03

12、-p -H M .H 40 43 03 H O 40 Oh *Jl IjH cd s 03 *H Ph P P pno 03 O O O r HP 43 Ph Ph 0 X H*h p, Oh *h -h X X BS cd J Oh 03 O ro LU 1 _J Li- LU 1- OJ _ O Q O 0 0 OJ Q1 I LA If the necessary test equipment is not available, alignment should not be 7. Harmonic Distortion Analyzer (Hewlett-Packard 333A at

13、tempted. For additional information, contact Customer Service Department, or equivalent) McIntosh Laboratory In., 2 Chambers Street, Binghamton, New York 13903 (telephone 607-723-3512). AM ALIGNMENT cqh a H Oj -P CD 0 0 2$ - o ad iH -P u o: ca d a CCS _ d -P o -p d -P o 3 c a bO p r? d p -o a a P o

14、ij o o rH 0 p o 0 H d o Ph 0 d d ii o P 0 0 o CO 0 o a Md p o 3 P P 11 0 Ph P d d 0 O d Ph a ?H d M H 0 O o cd o a a d d o p O -P C -p EH -P P P Cfl d 5 P d - -P W T3 O W S) d -P -P 3 d 0 0 c O rH C bO O d H O d P bOP d -P C O O iI 0 0 H 3P H bo E P -P aj H W P -p S M 0 P aJ O o O s a a oy o OJ o H

15、CP, (jr U O EH O a cj O -03 *EH -P 0 H a-p ?h o d o o o cj p Eh d o Eh aj O H -p 0 d O O c 0 bO p E a P O 0 O in O CJ a 0 p 4 C Ph -P o 0 0 0 a a s u p g O-H cd Ph d 0 0 -P d 3 d iI ctS a 0 O 0 a w 0 p 0pp o P bO 0 Ph O 0 0 C -P d d o cd -p H d p 0 o d o O -P OJ d a ii 0 0 P P d d d 0 p a o o d H H

16、P o d 0 P O d OH E p d d P rH O 0 p 0 d p Ph O 0 d c 0 0 bOd 0 0 3 PP aw 3 ad p P bO 0P 3 3 co o e-r I II P U -H x i P bD PC , s 0 P l-P EH 0 0 i1 P d d p 0 0 a 0 0 o a a 1 i E P SdVH d *H OJ Ph pop 2 P 3 a d a C OCP2P OJ 0 0 0 o p d g O Eh P d 0 Ph bO 0 d c p a bO O iI d d C a bO o a p o p p P 0 P

17、3 o a p p 3 to o o o 0 p O 5 3 !s O d Ph P 0 0 0 id d d Ph C d 0 c 0 P d P 0 O * p a 0 d ra d c cos d P 0 co O P 0 CCJ 0 d o d d Ph H Ui P P d O H 0 d o dJ O d a 3 d p d 2 d a a PH tfl S d d p o p o P P P d o 0 s a s a 0 a p p a d a p p 0 3 d ii OJ CO -d- a 0 P o d o iI Eh 1I O Ph d P d 0 d O P O o

18、3 a a = p p P 3 3 0 o a i p O 0 p d a o d S P n P d d 3 p d 0 p PPm n ap d p a d 3 O O iI d Oto d P . bOd OJ p 3 0 d o p pa p 3 O d d a p p p 0 o bO h p ap P 0 0 O 0 Sh d Ph P d a 0 d p d f 5 o p p Ph Ph a O P bO 0 C d H *H 0 d P Ph d 3 O P 0 h 3 d dd 0 o o E E Ph 0 d co p d d d ts o d P P d c p o b

19、Q d *H H p 0 C d O Ph p P 3 P 0 a d 0 P P *H p d o p d d p d a bo 0 d P P C 0 d O 0 d p a u P 3 0 P d d p , d a p i o d p o a P o p p p d P Ph O o 0 d p 0 0 0 H N O i P d H w o d p p d P p a d. o i p a -d mh o a o pH O d p bOHP 3 d o P o d d o oj Ph Ph a C O d d 0 d 3 oj p eh p oao a i d c d o d 1 d

20、 p p c OJ d d d a d o o p d d _ _ d d d d *h 3 a Ph d d o P o a o p a*d PjOPPhPPOm dO*H0d!3OO Eh OJ C_pd 0 H a u o d p h o Eh d d d d d d d C o Ph d 0 0 P 0 0 p P p p d d K c co d m 0 d -d- . .i- CS| CO to oo ap 0 0 bfj p P d 3 O O 0 . h n p a 0 H d P dO c3 d 0 rH 0 0 0 p d - OP ) 0 r-: d rH IS O O

21、C it OHEH LU VO a d p FM ALIGNMENT MULTIPLEX DECODER ALIGNMENT MR 73 iI cd h * -p ,n .a X 0 Eh O -P GO H. Q PS1A O P CJ OH 3 r-T x .c -P i 4-i f C- P -P ft w H OsS. w o.rix: c c +JH (D (D CO n .r, 3 h .G 0 C ft H CO W P H C *H O *H j CQ -P 3 G co cd CQ -P -H ,-H H X3 erf !. P-. C -P ft G O bO*H *H G

22、 *H ft CO H CO +J O -P *H -i co G co G co 0 rl J H ft c 3 X.4 O G d. EH gj g *H CO o P C O O ft H -P -P co H H o o P o ft o ft o (l) CO H G ft bl c ft ft ft co H w H H H H S cd CM P H ft H Td H ft O P Cd G ft c: n o H r-l G 0 H s O CM c ft H H O ft EH G H P Cd o ft CM - H H H , e ft H P =* ft ft ft

23、-ft- c ft H cd ft ft ft H O 0 ft ft O ft O H CM cd : P ft c * O G O G CO -4 G H cd co ft P H H o K H ft o o H O H O ft ft ft ft ft ft Td ftTJ ft C P p ft ft G X o P c o O (13 d co co Q co cd ft H 0 H CO ft M ft P ft o G X H P ft 0 ft CD H cd H o ft - ft p 00 P o G G ft ft G M P P G o P o P O CO -p f

24、t o X G H cd X O p o P Pft ft p 5 X ft c 0 H a H G G C/3 Tf cd (13 (13 o 1 O ft O H ft ii ft _ P o s P 0 +3 oo 03 P 0 2 O ft 0 C a ft p M ,q GO eft ft ft 0 cd ft ft o -P S S 0 c c cd ft bO 3 H ft co G CM M.c 0 00 H ft ft H H3 c cd o cd G bO c ft Pi X H h o o cd u 0 Pi Pi C o O G ft O bOft ft O 0 ft

25、*h .H Cd 0 (ftft cd co c Cs4 CO uo P 2 p ft ft o co -P cd co ft *H CO P 0 O P o ft C cd cd cd P T3 C 03 ft G bD -H H P cd o o C G ft bD cd cd ft ft G CO ft c ft C H -H bD ft O REPLACEMENT PARTS All parts not listed are common items Obtain able from radio parts jobbers. Replacement parts may be obtai

26、ned when ordered by PART NUMBER from: McIntosh Laboratory, Inc. Customer Service Department 2 Chambers Street Binghamton, New York 13903 (telephone 607-723-3512) Symbol N umber CAPACITORS Description Part N umber C2 3 Mylar 22pF 200V 064-087 C24 Mylar .1 pF 250V 064-086 Cl 1 1 El ect. lOOpF 15V 066-

27、127 C210 Tant. Elect. 1 . 5pF 35V 066-092 C218 El ect. lOOpF 15V 066-127 C301 Myl ar . 22 pF 50V 064-068 C305 El ect. lOOpF 15V 066-127 C308 Elect. 1 OOpF 15V 066-127 C31 3 Mylar * 1 pF 250V 064-067 C31 5 Myl ar . 22 pF 250V 064-068 C402,403 E1ect. lOpF 20V 066-149 C406,407 El ect. 22 pF 20V 066-148

28、 C410.411 El ect. 6.8pF 35V 066-146 C4l 3 Myl ar . 2 2 pF 250V 064-068 C41 4 Elect. 5/300/150/1000 250/60/60/25 066-145 DIODES D1 Ge. signal diode 070-003 0101,102 Ge. signal diode 070-003 0103,104 Ge. signa1 d i ode 070-003 D1 0 5,10 6 Si. signal diode 070-022 D201 Ge. si gna1 diode 070-003 D202,20

29、3 Ge. signal diode 070-003 D 301 Bias diode 070-046 D302.303 Si. signal d i ode 070-022 D304 Si. si gna1 diode 070-022 D305.306 Ge. signal d i ode 070-003 D307.308 Ge. signal diode 070-003 D401 Zener diode 16V 070-048 D402,403 S i . rectifier 070-031 D404 Si. rectifier 070-031 CHOKES LI FM antenna c

30、o i 1 122-069 L2 FM RF coi1 122-070 L3 Choke 1 .2pH 122-011 L4 Choke .47pH 122-010 L5 Choke 2.5pH 122-033 L6 FM mixer coil 122-071 L7 FM local oscillator coil 122-072 L8 AM Loop antenna 122-074 L9 AM antenna trimming coil 122-073 L1 0 Choke 2-5pH 122-033 L)01,102 Choke 75pH I22-013 L20 1 AM osci1 Ia

31、tor coil 122-066 L202 Choke 100MH 122-004 L301 Choke ImH 122-065 L302 Filter coil (19kHz phase) 122-080 L303,304 Filter coi1 (SCA) 122-079 TRANS 1ST0RS Q1 ,2 Si. j unction F.E.T. 132-049 Q3 Si. j unction F.E.T. 132-049 Q4 Si. N PN t ransis tor 132-015 Q5 Si. M.O.S. F.E.T. 132-064 Q201 Si. j unction

32、F.E.T. 132-049 Q202 Si. M.O.S. F.E.T. 132-064 Q203 Si. NPN transistor 132-041 Q204,205 Si. M.O.S. F.E.T. 132-061 Q301 S i . NPN t ransis tor 132-057 Q302 S i . NPN transistor 132-052 Q 30 3,304 Si. NPN transistor 132-057 Q305 S i . NPN transistor 132-057 Q306 Si. NPN t ransis tor 132-042 Q400.401 Si

33、. PNP transistor 132-056 Q402,40 3 Si. NPN transistor 132-041 Q404.405 S i . NPN transistor 132-052 Q406 Si. NPN t ran sis to r 132-072 Q407 Si . NPN transistor 132-041 POTENTIOMETERS R22 1 AM level control 134-177 R244 Volume cont ro1 134-217 R307 Muting cont rol 134-216 R309 FM level control 1 34-

34、197 R424 Separation adjust 134-212 R435 Meter adjust 134-197 F200 Fuse FUSES 5A Slo-Blo 089-020 MR 73 CHOKES FM antenna coi1 122-069 FM RF coil 122-070 Choke 1 . 2 (_iH 1 22-01 1 Choke .47pH 122-010 Choke 2.5nH 122-033 :H mixer coil 122-071 -M local oscillator coil 122-072 AM Loop antenna 122-074 AM

35、 antenna trimming coil 122-073 Choke 2 . 5pH 122-033 Choke 75pH 122-013 AM osci11ator coil 122-066 Choke 100MH 122-004 Choke ImH 122-065 ri 1 ter coil (19kHz phase) 122-080 ri 1 ter coi1 (SCA) 122-079 TRANS 1STORS Si . junction F. E. T . 132-049 Si . j unct ion F . E . T . 132-049 Si. NPN transistor

36、 132-015 Si. M.O.S. F.E.T. 132-064 Si. junction F.E.T. 132-049 Si . M.O.S. F.E.T. 132-064 Si . NPN transistor 132-041 Si . M.O.S. F.E.T. 132-061 Si . NPN transistor 132-057 Si . NPN transistor 132-052 Si . NPN t rans i s tor 132-057 Si. NPN transistor 132-057 Si. NPN transistor 132-042 Si . PNP t ra

37、nsistor 132-056 Si . NPN t ransistor 132-041 Si . NPN t ransistor 132-052 Si . NPN transistor 132-072 Si. NPN t ransis to r 132-041 POTENT 1OMETERS AM level control 134-177 Volume control 134-217 Muting control 134-216 FM level control 134-197 Separation adj us t 134-212 Meter adjust 134-197 RES 1ST

38、ORS R428 Wirewound 47n 5W 1 39-045 R429 Wirewound 2fi 5W 1 39-005 R430 Wirewound 2.7 1W 1 39-002 SWITCHES SI Antenna selector 148-019 S2 AM sensitivity 1 48-023 S3 Mode selector 146-135 S 301 Muting switch 146-136 S302 H.F. fi1ter switch 146-136 S401 Dial scale intensity 1 48-023 TRANSFORMERS T1 Ba

39、1 un 043-226 T2 FM IF transformer 162-042 T3 AM antenna matching trans. 162-043 T4 AM RF transformer 162-033 T1 01 FM disc riminato r 162-036 T201 AM 1F transformer 162-038 T202 AM IF t ran s fo rme r 162-038 T203 AM 1F t rans former 162-038 T 301 RF transformer (19kHz) 162-031 T302 RF transformer (

40、38kHz) 162-039 T 401 Power transformer 043-865 TUBES VI 6HU6 165-025 INTEGRATED CIRCUITS 1 Cl ,2 1n teg rated circuit 133-002 METERS Ml Signal strength meter 124-005 M301 Tuning Meter 124-006 CRYSTAL FILTERS XF-1 Crystal fi1 ter 044-045 X F-2 Crystal fi1 ter 044-045A LAMPS #1847 (meter lamp) 058-008

41、 #1866 (front panel) 058-014 #1828 (MPX lamp) 058-027 Festoon lamp (dial glass) 058-032 FRONT PANEL & TRIM Front panel 043-971 Front panel end caps 018-120 Tuning knob 043-272 Volume control knob 043-253 Mode selector knob 043-253 Muting knob 043-253 H.F. filter knob 043-253 Muting adj. knob 090-010

42、 MOUNTING SYSTEM Shelf bracket (right) 043-592 Shelf bracket (left) 043-593 Mounting template #100 038-179 Hardware package 043-446 MISCELLANEOUS ITEMS FM dipole antenna 170-033 Dial glass 044-079 Pointer 043-876 Dial cord (complete) 043-891 Fuseholder 178-001 AC power cord 170-021 Shipping carton 0

43、43-988 Owners manual 038-448 Plastic feet 017-041 Push terminal (antenna) 074-032 Audio cab 1e (61) 170-015 LDR network 144-013 1 5C0820S7-M0470 MR73 S.B. No. 1 SERVICE BULLETIN FM-RF AMPLIFIER MODIFICATION MODEL: MR73 FM/AM Tuner PURPOSE OF MODIFICATION: To decrease power dissipation in transistor

44、Q2 WHAT UNITS ARE AFFECTED: Serial No. 10T01 to 27T84 Only. WHEN MODIFICATION SHOULD BE MADE: When the customer complains that FM sensitivity has decreased or FM tuner has become noisy. MclNTOSH MODIFICATION KIT NO.: 044-175 PARTS REQUIRED: (Supplied in Kit) QUANTITY PART NUMBER 1 132-049 1 136-396

45、DESCRIPTION cgs FET transistor 220fi 10% 1/4W resistor J, C / / (e PROCEDURE: (Refer to the diagram on reverse side) Step 1 Remove bottom cover and bottom cover of RF front end. Step 2 Replace transistor Q2. Be sure leads are of same length and have same positioning as used on original transistor St

46、ep 3 Counting from the front of the tuner, locate the fourth feed-thru capacitor on the left side of the RF front end. Remove the red lead and connect it to the unused second feed-thru capacitor. Remove the 220ft 10% 1/4W resistor (R2) connecting between feed-thru capacitors 3 and 4, and connect this resistor between feed-thru capacitors 2 and 3* Co